How to keep New York afloatAn Environmental Article from All-Creatures.org

From

Sea levels have risen almost a foot in the past
century, partly because of ice melt and thermal expansion (warmer water has
more volume), and partly because of naturally occurring land subsidence of
the Northeast. In the same period, area temperatures have risen nearly 2
degrees F. About two-thirds of that increase occurred in the past 30 years
and sea-level rise has accelerated in the past decade.

Like many New Yorkers, Radley Horton often frets about tomorrow's weather.
Unlike many, it's his job. A scientist at NASA's Goddard Institute for Space
Studies (GISS) and coauthor of a forthcoming study on the effects of climate
change in New York City, he is particularly concerned about an
often-overlooked aspect of global warming: bigger, stronger storms.

"It's not a linear relationship," he says on a subway ride to Manhattan's
South Ferry station, which would be mostly underwater in a Category 2
hurricane. "A little bit warmer sea surface equals the potential for a lot
stronger storm." And feeding off the greater ocean warmth, full-blown
hurricanes may arrive at New York City with increasing regularity.

By 2050, stronger storms and rising sea levels may make the flood that
previously hit once every 100 years a once-in-20-years event, according to
GISS. With a possible three-foot sea level rise by 2100, flooding could
occur every four years. "Our old ideas about climate may have to change," he
says. "We need to be open to all possibilities."

Even as high-profile politicians like California Gov. Arnold Schwarzenegger
and New York Gov. George Pataki pledge to reduce their states' carbon
"footprint," cities like New York and London - and entire countries like the
Netherlands - are moving to adapt to long-term climate change.

With slogans like, "Why should you worry about a hurricane? It's not like
you live on an island" and a tripling of storm shelters since Katrina, New
York City's Office of Emergency Management has prepared for at least some of
the short-term possibilities.

But even before Katrina, the city's Department of Environmental Protection
(DEP), which manages the city's freshwater supply and wastewater - 13,000
miles of pipe, total - formed a task force with GISS to look at the
long-term effects of climate change.

Among other things, the DEP was concerned by the damage storm surges might
inflict on a city surrounded by water. Although city officials declined to
discuss concrete solutions for this article saying they were still in the
"assessment" phase, scientists foresee potential fixes ranging from raising
key infrastructure and building dikes, to flood gates and temporary seals
over tunnel entrances. One group proposes raisable flood barriers large
enough to protect all of Manhattan Island.

Sea levels have risen almost a foot in the past century, partly because of
ice melt and thermal expansion (warmer water has more volume), and partly
because of naturally occurring land subsidence of the Northeast. In the same
period, area temperatures have risen nearly 2 degrees F. About two-thirds of
that increase occurred in the past 30 years and sea-level rise has
accelerated in the past decade. "The core body of knowledge has solidified"
on climate change, says Cynthia Rosenzweig, the lead GISS scientist on the
climate-change task force. "We're moving into a solution phase."

But possible solutions - and how to pay for them - are still "big question
marks," says Gary Heath, director of bureau operations and environmental
analysis at the DEP. Although antiflooding technologies are basic and well
established, implementing them in a city as old and crowded as New York is
no simple task.

Elevating roads, for example, sends more runoff into subway grates. Water
pumped out of subway tunnels - already some 14 million gallons daily - goes
into sewer systems that might be overtaxed by rainwater. "You solve one
problem and you create another," says Madan Naik, chief structural engineer
of New York City Transit. "It's got to be a collaborative effort, whatever
we do."

Much of this city of 8 million, the largest and most densely populated major
city in the US, is only 10 feet above sea level. The potential 30-foot storm
surge accompanying a Category 3 hurricane would flood large swaths of south
Brooklyn, parts of Queens, Staten Island, and Manhattan below Canal Street,
including the World Trade Center site - 100 square miles total. As happened
during a 1992 northeaster, floodwater might pour into the city's tunnels and
subway system, many of whose entrances are but 10 feet above sea level,
short-circuiting public transportation and stopping traffic. The city's
wastewater treatment plants - all 14 of which lie at the water's edge and
have outfalls at mean tide level - could back up, sending raw sewage into
basements and bathrooms citywide.

Klaus Jacob, a special research scientist at the Lamont-Doherty Earth
Observatory at Columbia University in New York, estimates the cost of such
an event up to $100 billion. That's one-tenth of the $1 trillion gross
regional product of the New York metropolitan area, embracing three states
and 22 million people. (Some estimate that Katrina will cost Louisiana and
Mississippi up to $150 billion.)

Rather than individually shoring up the city's many vulnerabilities, the
better solution is to use the region's topography, say engineer Douglas Hill
and Malcolm Bowman, head of the Storm Surge Research Group at Stony Brook
University. Three barriers placed at strategic "choke points" - the
Verrazano Narrows, Throgs Neck, and the Arthur Kill - would protect all of
Manhattan and half the entire flood-prone area, they say.

Similar smaller barriers already protect Providence, R.I., New Bedford,
Mass., and Stamford, Conn. Completed at a cost of £535 million in 1982 ($2.1
billion in today's dollars), the Thames River Barrier, about the size of the
one proposed for the Arthur Kill, has been raised more than 90 times. Italy
plans to finish its MOSE project, a series of inflatable pontoons to protect
the Venice Lagoon, by 2011.

And then there's the Netherlands: Half the nation is below sea level. Its
colossal Eastern Scheldt barrier, nearly two miles long and often called the
"eighth wonder of the world," most resembles the one proposed for the
mile-wide Verrazano Narrows.

Human nature being what it is, Mr. Bowman doesn't see construction beginning
any time soon. Without exception, the aforementioned barriers were built
after - not before - major floods. The British and Dutch barriers were built
after a 1953 North Sea storm caused major loss of life in both countries.
The New England barriers rose after the "Long Island Express" hurricane of
1938.

In fact, in the 1960s the Army Corps of Engineers proposed something similar
to block storm surges from Lake Pontchartrain, which abuts New Orleans.
Never built, the barriers "might have made enough of a difference" during
hurricane Katrina, says Bruce Swiren, a mitigation specialist at the Federal
Emergency Management Agency. The disaster has led him to reconsider Bowman's
idea. "I used to think that it was a complete pie in the sky," he says.
"After Katrina, I'm starting to think maybe it's not such a crazy idea after
all."

But Klaus Jacob, author of several papers on New York's vulnerability to
flooding, opposes such large-scale solutions not on engineering but on
philosophical grounds. They lend an "illusion of protection" that will only
prove catastrophic in the end, he says. "The higher the defenses, the deeper
the floods that will follow," he says.

Commonsensical preparations such as raising houses; putting electrical
infrastructure in the attic, not the basement; and formulating clear
contingency plans will go much further. In the end, however, Jacob sees only
one viable, long-term option: Retreat from low-lying areas.

"That's the lesson learned," he says, the "price to be paid for pumping CO2
into the atmosphere."

Fair Use Notice: This document, and others on our web site, may contain copyrighted
material whose use has not been specifically authorized by the copyright owners.
We believe that this not-for-profit, educational use on the Web constitutes a fair use
of the copyrighted material (as provided for in section 107 of the US Copyright Law).
If you wish to use this copyrighted material for purposes of your own that go beyond fair use,
you must obtain permission from the copyright owner.